Living cooperatively in a culturally diverse world is one of the great challenges of our time. This issue has become especially salient in the United States as record numbers of immigrants are crossing the southern border, many of them illegally. People often fear immigrants because they are "not like us," suspecting that they will break our laws, undermine our values, steal jobs, and receive undeserved benefits.
Psychologists have long studied two contrasting attitudes toward people "who are not like us"—that is, members of out-groups. Prejudice is a fear-based, negative evaluation toward people who look and act differently from us. Fear and suspiciousness toward members of out-groups exist in all of us to some degree, apparently a tendency encouraged by the natural selection that has occurred in the long evolutionary history of conflicts between different human groups. But prejudice is also an individual-differences variable, which means that some people have stronger prejudices than others. Berkeley psychologists Nevitt Sanford, Elie Frenkel-Brunswik, and Daniel Levinson studied anti-Semitism in the aftermath of World War II, seeking to understand the Nazi prejudice that led to the Holocaust. Joined by political philosopher Theodor Adorno, they developed the California F-scale, a measure of the authoritarian personality syndrome, which includes high levels of prejudice against members of out-groups (Adorno et al., 1950).
A second attitude toward out-groups studied by psychologists is social tolerance. Social tolerance is a tendency to counteract prejudice, a willingness to tolerate those whose appearance and practices differ from our own. Prejudice and social tolerance seem to emerge from two different areas of the brain. Prejudice occurs with activation in the amygdala, the center of fear and anger. Social tolerance occurs when the prefrontal cortex activates, damping down signals of fear from the amygdala (Sapolsky, 2023).
Prejudice and social tolerance, centered in two different parts of the brain, are two different psychological tendencies, not just opposite ends of the same trait, although it has taken psychologists years to realize this. For example, when Harrison Gough constructed the Tolerance Scale of the California Psychological Inventory (CPI), he began with MMPI items that predicted an anti-Semitism scale developed by Levinson and Sanford. The CPI Tolerance Scale is essentially an anti-Semitism scale scored in reverse, implying that tolerance is simply the opposite of prejudice (Megargee, 1977). Research on the five major personality factors has indicated that the factor openness to experience correlates negatively with prejudice and positively with social........